Field of the Invention
The embodiments of the present invention relate to a field of photovoltaic (PV) power generation technology, and more particularly, relate to a PV junction unit, a PV junction box having the same, and a method for monitoring a current in each PV string of a plurality of PV strings which are then joined into a single string.
Description of the Related Art
In current PV power generation systems, in order to reduce wires between PV cells and an inverter, PV cells of the same spec are first connected in series to form a PV string, then a plurality of PV strings are introduced into a PV junction box in a parallel way, the PV strings are joined in the junction box to form a single string, and then the formed string is led out to the inverter.
The current PV junction box usually comprises a fuse, an anode busbar, a cathode busbar and a circuit breaker, wherein for the plurality of PV strings, an anode output end of each PV string is connected to an anode busbar via the fuse, and an output end of the anode busbar is connected to an anode input end of the circuit breaker; a cathode output end of each PV string is connected to a cathode busbar, and an output end of the cathode busbar is connected to a cathode input end of the circuit breaker; and an anode output end and a cathode output end of the circuit breaker are connected to the inverter.
In order to exactly know the operation state of each PV string in time, it is necessary to monitor the current in each PV string.